Cat C15 coolant in intake of the head, Oil is clean? Recent in frame.

I dont think this could be anything except a pre-cooler. If you did have compression leaking past a fire ring/ head gasket, it is unlikely the result would get coolant all the way around to the intake. If it did leak coolant internal it would leak in cylinder and cause hydolock or drain to the crankcase.

Under hard pull the boost pressure exceeds cooling system pressure on the precooler forcing air in the coolant. When the boost is below coolant pressure or when setting, it can leak coolant. I get you said it was dry.....I would pop the pipe off hot and leave cooling system pressure on overnight and see if anything shows up. My vote is the pre- cooler.

Not a strong Cat guy, but maybe others will voice an opinion.

CAT does not use EGR.

Please share ESN so we all know the exact engine you have.

Thanks

 

I'm definitely not an expert on anything but a cat with coolant in the intake couldn't be anything but the pre-cooler, could it?

 

There shouldn't be EGR on that engine. That didn't come out until a few years later with the SDP I think.

 

Coolant residue or actual coolant? Could be cracked head.